This application claims the benefit of Korean Patent Application No. 2002-30690, filed May 31, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an image forming device, and more particularly, to an image forming device capable of correcting vertical alignments, and a correction method thereof.
2. Description of the Related Art
In general, an image forming device, such as a photocopier, a scanner, a printer, and so on, picks up a sheet of printing paper one by one from a paper-supplying cassette, passes the printing sheet through predetermined traveling passageways, and moves the printing sheet to a feeding position where feeding rollers are driven to feed the printing sheet. The printing sheet positioned in the feeding position travels at a proper time and feeding speed by the feeding rollers driven by a controller upon a print command and is printed with images by a printer head.
For example, in a case that dots of the printer head are 832 dotsxc2x10.016 (0.5 dot/800 dpi) and in a case of 1 pass of the 832 dots, a rotation radius or distance of a feeding roller (outer circumference CD=56.8 mm) is theoretically the same as the following Formula 1.                                                                         Size                ⁢                                  xe2x80x83                                ⁢                of                ⁢                                  xe2x80x83                                ⁢                a                ⁢                                  xe2x80x83                                ⁢                dot                            =                            ⁢                                                                    1                    ⁢                                          xe2x80x83                                        ⁢                    inch                                    800                                =                                                      0.03175                    ⁢                                          xe2x80x83                                        ⁢                    mm                    ⁢                                          xe2x80x83                                        ⁢                    1                    ⁢                                          xe2x80x83                                        ⁢                    pass                                    =                                      832                    ⁢                                          xe2x80x83                                        ⁢                    dots                                                                                                                                          Total                ⁢                                  xe2x80x83                                ⁢                size                ⁢                                  xe2x80x83                                ⁢                of                ⁢                                  xe2x80x83                                ⁢                832                ⁢                                  xe2x80x83                                ⁢                dots                            =                            ⁢                                                0.03175                  xc3x97                  832                                =                                  26.416                  ⁢                                      xe2x80x83                                    ⁢                  mm                                                                                                                        turn                :                                  1                  ⁢                                      xe2x80x83                                    ⁢                  pass                                            ⁢                            =                                                26.416                  56.80                                =                0.46507                                                                        Formula        ⁢                  xe2x80x83                ⁢        1            
That is, in a case that the printer head makes one pass, the feeding rollers make about a half turn. However, the above result is a theoretical result, such as a tolerance error (xc2x1xcfx860.02xcfx80) occurring due to a diametric allowance of the feeding rollers, and a structural error, that is, a vertical alignment, produces white lines and black lines.
The white lines and black lines deteriorate a quality of images formed by the image forming device. In order to solve the above problem, a conventional image forming device corrects feeding error values using a predetermined correction value selected by a user.
However, the feeding error values are different depending upon print modes, printing sheets (thickness), and printing position sections of printing sheets, so that the feeding error values should be corrected depending upon respective modes in order to correct the feeding error values more precisely.
In general, operation modes, referred to as the xe2x80x98print modesxe2x80x99 hereinafter, of a printer are divided into print quality modes, such as Draft (full swath), Normal (full swath*xc2xd), Quality (full swath*xc2xc), and Best (full swath*xe2x85x9, ⅙), and the printing sheets of paper are classified into Plain, Glossy, Transparency, Special Media, and so on, according to their thickness. For example, a thickness of the printing sheets is different from others and ranges from 0.1 mm at minimum to 0.67 at maximum or so. Further, the printing position sections of the printing sheets are divided into a first section where a printing sheet is inserted in a pickup roller and feeding rollers, a second section where the printing sheet is inserted in the pickup roller, the feeding rollers, and exit rollers, a third section where the printing sheet is inserted in the feeding rollers and the exit rollers, and a fourth section where the printing sheet is inserted in the exit rollers, and over-feeding of the printing sheet occurs at the instant that the printing sheet is inserted in respective sections.
Accordingly, the conventional corrections for the feeding error values have been made using the predetermined correction value in a lump with respect to the feeding error values appearing different depending upon the print modes, the printing sheets, and the printing position sections, so that the corrections for the feeding error values have not been accurately made.
In order to solve the above and/or other problems, it is an aspect of the present invention to provide an image forming device and a correction method thereof which enable feeding error values (vertical alignments) to be corrected depending upon, firstly, print modes, secondly, printing sheets, and, thirdly, printing position sections for the printing sheets.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
In order to achieve the above and/or other aspects, an image forming device according to an embodiment of the present invention includes a first calculator applying one of setting values for plural alignment patterns pre-set in accordance with magnitudes of feeding error values corresponding to feeding amounts of a printing sheet of paper by feeding rollers to calculate first correction values for the feeding error values depending upon operation modes, a second calculator calculating second correction values for the feeding error values depending upon the printing sheet, and a controller controlling the feeding rollers to be driven to correct the feeding error values depending upon the operation modes and the printing sheet using the first and second correction values calculated by the first and second calculator.
Further, the image forming device includes an input part inputting the setting values corresponding to the feeding error values and a detector detecting the feeding error values, and the first and second calculators calculate the first and second correction values depending upon the operation modes and the printing sheet, respectively, using the setting values.
In the meantime, the image forming device has a printing position section divided into a first section where the printing sheet of paper is inserted in a pickup roller and feeding rollers, a second section where the printing sheet is inserted in the pickup roller, the feeding rollers, and exit rollers, a third section where the printing sheet is inserted in the feeding rollers and the exit rollers, and a fourth section where the printing sheet is inserted in the exit rollers, and the first and second calculators apply the setting values corresponding depending upon the printing position sections from the setting values of the plural pre-set alignment patterns to calculate the correction values for the feeding error values depending upon the operation modes and the printing sheet. The controller controls the feeding rollers to be driven to correct the feeding error values depending upon the printing position sections, the operation modes, and the printing sheet using the correction values calculated by the first and second calculators.
In the meantime, a vertical alignment correction method for an image forming device includes printing plural alignment patterns pre-set according to magnitudes of feeding error values corresponding to feeding amounts of a printing sheet of paper by feeding rollers, inputting predetermined setting values for the feeding error values, calculating correction values for the feeding error values depending upon the predetermined setting values inputted, and correcting the feeding error values depending upon the operation modes using the calculated correction values.
Accordingly, the image forming device and the correction method thereof can correct the feeding error values depending upon the operation modes, the printing sheets, and the printing position sections, to enable best quality images to be obtained in respective modes.